Open Context

Project

China Ceramic Petrography Database

Overview:

This database seeks to incorporate petrographic data from archaeological ceramics and geological sources across China in order to make it available in Chinese and English as a comparative reference collection. While the initial focus is on materials from the Neolithic and Early Bronze Age period in northwestern China, the eventual goal is that contributions from other petrographers working across the country will allow for the expansion of the database both geographically and chronologically. In order to add data to the site, please first contact the site editors directly and use this template for entering your data. Consult the "Database Category Notes" or contact the editors directly if you have questions regarding data entry and formatting. Eventually we hope that petrographers working on new materials will be able to easily search for similar ceramic and geological materials in order to inform their own research and to allow for a better understanding of connections between ceramics and sources throughout the country.

The initial dataset is composed of more than 250 archaeological ceramic samples dating to the Majiayao and Qijia periods in southern Gansu Province. Around 30 geological samples including clay, sand, and rock from known archaeological sites in the area are also included. This initial dataset was collected as part of the Tao River Archaeological Project, an international collaboration between Harvard University, Beijing University, and the Gansu Institute of Archaeology, and is a mixture of sherds collected from surface survey and excavation at four sites in the northern Tao River Valley. While exact sampling methodologies vary by dataset, each is either a total sample or a stratified random sample of the available data. Notes on exact sampling strategies are provided for each individual dataset. All samples, with the exception of some geological materials were thin sectioned at the Beijing Geological Museum Ceramic Petrography Workshop and then were examined at Yale University and Shandong University.

While a number of techniques are available for petrographic analysis, this initial dataset was examined using a combination of qualitative and quantitative methods as outlined in Whitbread (1995) and Stoltman (1989; 1991; 2001; 2015), respectively. While this database will not require that these exact methods be followed, it is hoped that the general methods given in the Methodological Notes section of the website will be followed in order to allow for ease of comparison between datasets. Individual methodological notes will accompany all datasets and will outline any deviations from those given here. Results for individual samples are displayed for both qualitative and quantitative analysis and also include notes from the survey or excavation context, macro analysis of the sherds, images of the whole sherd, and pictomicrographs of the thin section.

Data from petrographic research from across China is welcome to be added to the website, with curation of the data taking place as a collaboration between the database curator and the contributor. All data will eventually be available and searchable both in Chinese and English. All data placed on this website is citable. For citation information please see the citation notes at the bottom of each page.

Methodological Notes:

In order to make use and comparison of these datasets as straightforward as possible please read through the following guidelines before submitting (and preferably before analyzing) your data for inclusion in the database. You can use the spreadsheet temple provided here to record your data. While not all of the information below is required for inclusion, the more you can add the better the results!

General Sample Information: This section should include information on find location, find context, approximate time period, cultural affiliation, sampling strategy, surface treatment, color, and vessel type (if known). If you have questions about sampling strategies please see Drennan’s Statistics for Archaeologists (2010).

Petrographic Information (Qualitative): Petrographic data will vary based on the techniques used. Ideally for this database a combination of qualitative and quantitative data will be provided. If only qualitative analysis is undertaken then techniques outlined by Whitbread (1995), Appendix A3.2 should be generally followed. This ideally includes descriptions of C/F/V ratios; size and shape of voids; grain size distribution; homogeneity, color, optical activity, and birefringence of the groundmass; description of texture; description of inclusions noting predominant, frequent, few, rare, and very rare inclusions; presence of textural concentration features, amorphous concentration features, and/or crystalline concentration features. At the very least a description of the inclusions and C/F/V ratios is required.

Petrographic Information (Quantitative): If point counting is used in addition to qualitative analysis, then please follow the general methods laid out by Stoltman (1989; 1991; 2001; 2015) in his articles on the subject. While certain attributes of this method, such as the sand and temper size indices, do not need to be included, the actual method for counting, including use of a movable stage set to 1mm intervals and his categories for inclusion sizes, should be followed. At least 120 points should be counted for each sample, with sample rotation and recounting used if the sample size is too small to achieve this number in a single count. If point counting is used, then some aspects of the qualitative assessment can be skipped, such as C/F/V rations and description of inclusions, since these will be effectively replaced by the point counting results. Both raw counts of matrix, silt, sand, temper, and voids as well as ternary plots of these results will ideally be provided.

Fabric Grouping: This includes a general descriptive term that covers the predominant or notable inclusions in the fabric of the sample. For example, if the sherd predominantly has quartz and feldspar inclusions with no notable accessory minerals then this may be termed a Quartz-Feldspar Fabric Group. In order to simplify searching of the database, please check to see if an identical fabric to what you are describing has already been noted on the website. If so, please use this fabric description instead of creating your own. This can be done in consultation with the database curator.

Geological Associations: If you can confidentially associate the fabric of a sherd with known clay or temper sources then please note this association. Discussion of your confidence in this association can be undertaken with the database curator before a final decision on inclusion is made.

Geological Samples: Geological samples of rocks, clay, and/or sand are also welcome in this database. Requirements for information on geological samples for the database is still evolving, so please contact the database curator for more information. Point counting for clay samples is ideal. Any associations between geological samples and ceramics should be noted.

Images: At least one PPL and one XPL pictomicrograph of each sample is necessary for inclusion on the website. Samples without images may be considered in some cases. Ideally multiple images at multiple zoom levels and focus on various inclusion types is ideal.

Potential Applications of the Data:

Currently the field of ceramic petrography in China is very small and for many regions there are no datasets available. Even if petrography has been undertaken, it is very difficult to gain access to this data and there are no standardized methods or formats for displaying and sharing it. The first goal of this database it to help newcomers to the field by providing a standardized form for recording and sharing petrographic data and a location where they can compare their own results with the work of others. The second goal is to provide access to as many ceramic and geological samples as possible so that scholars can begin to make connections between materials used in various locations and time periods in China. Currently most cultural connections and boundaries are based on ceramic typology alone, with little attention paid to whether forms that are similar actually were made using similar raw materials. The hope is that this data can be used to further refine our understanding of ceramic production, exchange, and social interaction in early China. Finally, this database will act as a jumping off point for other aspects of ceramic data, including chemical analysis, use-wear, and other methodologies that hopefully will eventually be incorporated into a larger ceramic analysis database.

Support:

The creation of this database would not be possible without generous funding from the National Science Foundation (Dissertation Improvement Grant #1086761). The research into the foundational dataset for this database was also made possible by the support of the Fulbright Foundation, the Yale University Council on East Asian Studies, and the Yale University MacMillan Center. Laboratory facilities were kindly provided by the Yale University Department of Anthropology and Shandong University. Many thanks also to individuals who have advised and contributed to this research including Dr. Anne Underhill, Dr. Rowan Flad, Dr. Wang Hui, Dr. Li Shuicheng, Zhou Jing, and Yu Changfu.

China Ceramic Petrography Database Category Notes

General Information Categories:

OPEN CONTEXT ID: This unique alphanumeric identifier (URI) will be created by Open Context and assigned to each sample added to the database in order to identify it among all other submitted samples. You may leave this field blank.

SAMPLE ID: This is alphanumeric text that identifies a sample uniquely within the context of a project and is used for locating records specific to that project.

SITE: This denotes the archaeological site that the sample was taken from. For samples collected through survey the nearest local town or the country can be noted instead.

CULTURAL AFFILIATION: If the sample comes from a known archaeological culture or subphase of a culture please note that here.

CONTEXT: Here the context in which the sample was collected should be noted. Examples include surface collection, excavation, or road cut.

LATITUDE and LONGITUDE: Latitude and Longitude: Please provide general geospatial coordinates for the sample from a GPS or other source; decimal degrees (latitude, longitude) using the WGS84 standard is preferred. Please convert other projections (such as UTM) to this system before submitting your data. If you have concerns about sensitive location information, please reduce the precision of the geospatial information and provide a description of your method (such as "reduced precision by removing numbers after the decimal point" or "randomized within a 5 km buffer").

SAMPLE TYPE: If possible, please specify what part of a ceramic vessel or object was used to create your thin section. Examples could include body, rim, neck, shoulder, base, or handle. If you are using a different naming convention for ceramic parts please convert your terminology to match our system. If you have a part that is not yet entered in the database or in the examples provided here, please note this in your submission.

MACRO PASTE ASSESSMENT: Many projects and researchers do a general macro assessment of a sherd before producing a thin section; this often includes a general assessment of the paste type. In this category please record your macro assessment of the paste. This can include Fine (no inclusions visible), Fine Sand (only very small inclusions visible), and Coarse Sand (frequent, large inclusions visible). If you feel that other terminology is appropriate for your samples please note this on submission along with a description of your terms.

SURFACE TREATMENT: This category will be as variable as the many surface treatments seen on ancient pottery. In an effort to standardize entries in this category please refer to the descriptions and photographs provided for each type.

Plain: There is no visible surface treatment.

Paint: Pigment of any type or color has been used to decorate the surface.

Cord Mark: Cords, with a distinctive twill, have been impressed on the surface.

Crisscrossed Cord Mark: Cords have been used to create a crisscrossed patter on the surface.

Basket Mark: Wide, shallow, parallel impressions have been made on the surface.

Incision: Sharp, deep lines or holes have been incised into the surface.

Grid Incision: Crisscrossing incised lines have been cut into the surface.

Comb: Shallow, parallel lines have been created using a comb-like device.

Impression: Fingers or tools have been used to create lines or other designs on the surface.

Applique: Clay has been added to the vessel surface to form a decorative design.

A note on slipping and burnishing: While slipping and burnishing can be visible to the naked eye, it is often difficult to accurately identify these in many cases. Since these surface treatments are more readily visible in thin section, please provide information on these surface treatments in that portion of the database.

COLOR: Please note the general color of the sherd. If the sherd varies between the inside and outside, please list the external color/internal color, such as Grey/Orange. While we realize color is highly subjective, photos provided will hopefully help clarify this section.

VESSEL TYPE: When known, please provide information on the type of vessel from which a sherd was taken for your sample. While terminology varies greatly between regions and time periods, please try to use terminology that is common in the literature for your region.

SHERD PHOTO REFERENCE: This alphanumeric will connect your entries in this table to the photos you have provided.

EXTERNAL PHOTO: Please provide one or two photos of the whole sherd from which the thin section was made.

PICTOMICROGRAPH: Please provide between one and five photos from your thin section. Ideally, please provide a mixture of polarized and cross-polarized images at various scales. Please also provide a scale bar in each photo.

REFERENCE/CONTACT: Here we will record information on how to contact the individual or project members who have submitted each sample. While this database serves as a reference for ceramic petrography being undertaken across China, we know that to accurately compare samples simple descriptions, data counts, and images are not enough. We hope that this database will allow you to get in touch with petrographers from across the region in order to more directly compare and share data.

TEMPER: Please mark as Yes/No/Unclear depending on the presence, absence, or ambiguity of human added inclusions in the paste.

Q TEMPER: Estimated percentage amount of temper (temper is usually distinguished from natural inclusions based on the more pronounced angularity of the anthropogenic inclusions; if in doubt then fill in “unclear” under TEMPER and leave the Q TEMPER blank)

MAX GRAIN SIZE: Maximum grain size of largest inclusion.

AVG MAX GRAIN INCLUSIONS: average maximum grain size of large inclusions (measurements taken on all inclusions above fine sand size visible in thin-section and averaged out).

OPTICAL ACTIVITY: Is the fabric of the sample optically activity? Please record as active, moderately active, or inactive.

DISTRIBUTION: Please record whether temper in the sample is distributed regularly or irregularly using the categories: well-homogenized; sufficiently homogenized; poorly homogenized (please use the same chart as for sorting).

MAX VOID SIZE: How large is the largest void in the sample?

AVERAGE VOID SIZE: How large are the voids in the sample on average?

VOID SHAPE: Please record whether the majority of voids are: angular; subangular; subrounded; rounded. For a description of each category please see Whitbread (1995, P. 380, Table A3.3) for a description of each category.

FREQUENT INCLUSIONS: Please record which inclusions are most frequently seen in the sample.

COMMON INCLUSIONS: Please record which inclusions are commonly seen in the sample.

RARE INCLUSIONS: Please record which inclusions are rarely seen in the sample.

SLIP/BURNISH: Record whether any slipping or burnishing is observed on the sherd.

POSTDEPOSITIONAL NOTES: Record whether you have seen any inclusions or concretions, such as calcite, that appear to have developed after the sherd was deposited in the ground.

LOCAL FABRIC GROUP: Based on your assessment of the types and amounts of inclusions, as well as any other petrographic work that has been done in the region, please classify the sample into a specific fabric group. If no previous work has been done in your region, or if you sample does not match any previously identified groups, please provide a group name to classify the sample. Additional information on your classification technique can be provided in the Notes category.

GEOLOGICAL ASSOCIATION: If you can confidently relate the ceramic paste to a specific geological formation or general rock type please note that here.

NOTES: Here you can note any additional information about the sample that is not provided in another category.

Quantitative Categories:

For detailed information on how to undertake point counting on ceramic thin sections please see Stoltman (1989; 1991; 2001) for detailed information on each step in this methodology. Between 120 and 300 points should be counted for each thin section. While you may record many metrics for each point, in the Quantitative section we will only be including percentage amounts from each category. Additional information can be provided in the Qualitative section.

MATRIX%: Percentage of points that are identified as clay matrix.

SILT%: Percentage of points that are identified as minerals up to 0.0625mm in size.

SAND%: Percentage of points that are thought to be natural inclusions from .0625mm and above in size. If you record individual size categories it is suggested that you follow Stoltman’s (1989) classification system: fine (.0625-.25mm), medium (.25-.5mm), coarse (.5-1mm), very coarse (1-2mm), and gravel (>2mm).

TEMPER%: Percentage of points that are thought to be human-added inclusions. If you cannot distinguish between natural and human added inclusions please make a note of this is the Notes category and leave the temper section empty.

VOID%: Percentage of points that fall on voids in the thin section.

Current Disposition of the Physical Collection:

All thin section samples belong to the entity controlling the original ceramic sherds from which the samples were taken unless otherwise noted on the sample page. Due to the ongoing nature of research, samples may currently be in the possession of contributing researchers; otherwise they will be housed alongside the original sherds. A note of location will be provided for each sample. Currently all samples listed above are in the possession of Andrew Womack.

About the Authors:

Andrew Womack is currently a lecturer in East Asian Archaeology at McGill University and a visiting scholar at the University of Toronto Archaeology Centre. His research focuses on using geophysical survey, excavation, and ceramic analysis to explore craft production, identity, and interaction in late Neolithic and early Bronze Age northwestern China. He is Associate Director of the Tao River Archaeology Project and the creator and editor of the China Ceramic Petrography Database.

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